Using nanotechnology for water treatment

Using nanotechnology for water treatment

The dire situation of Cape Town’s water shortage cannot be overestimated. Dam levels have dropped as low as 28%, with only 18% of the available water fit for consumption. On World Water Day, celebrated on 22 March, COSATU called for the scarcity to be treated as a national crisis and urged for ‘national intervention’ which focused on properly maintained water infrastructure and water harvesting mechanisms. There are short, and long term solutions and scientists like Profesor Jane Catherine Ngila, lecturer and former Head of Applied Chemistry at the University of Johannesburg, are looking at how nanotechnology can be used in water scarce areas.

Ngila spoke at Scifest Africa earlier this month and delivered a lecture titled ‘Why and how do we manage water quality in South Africa?’ Her current research at the University of Johannesburg focuses on nanotechnology for water treatment and water quality monitoring.

What Profesor Ngila has created with her team are nanoscale filters which have the power to filter and purify water. These filters can be used for large scale production, as well as domestic water purification purposes. This is useful when water resources are scarce and cheaper purification methods are required to ensure domestic scale water quality.

“If my research can contribute towards producing low cost filters, so that we can supply it in the rural areas so that [people] at home can have access to that safe water and they can treat water localised in their small scale filters, then I would have made a difference in the world.”

The world of water under a microscope

“Nanotechnology is a technology or a science that looks at the interaction of substances at a small scale. What that means is we can be able to see things on a very small scale, things we can’t see with the naked eye so we have technology such as scanning and very powerful microscopes, with which you can see substances,” she said.

Nanotechnology has been used in countries including Australia, Germany and the USA for water filtration processes, however Ngila is spearheading research into filtering technology in South Africa. “Once we have got a breakthrough and we can produce prototypes and they can be upscaled to commercial [filtering] products,” she said.

“We are working towards looking at what is already in the market and see how we can improve the performance of our new product so that they can have a better performance and also customise that for local use for purification in South Africa.

“But there have been numerous challenges along the way, especially because while the nanoparticles in the filter are used to make the water safe for consumption, they can also pose a risk if used incorrectly.

“The job of these nanoparticles is to kill bacteria, like silver oxide, magnesium oxide, zinc oxide. But the problem is that when you try to incorporate the nanoparticles on the filter, there is the danger that they can also leech out, and if they leech out of the material, then you end up with secondary pollution and we don’t want that. Secondary polution is when the water you are trying to treat is contaminated by the very same material that you are using to filter the water,” she said.

Although South Africa has been declared one of 30 water stressed countries by the World Health Organisation, drought and poor water quality management is a problem all over the continent, even in her home country, Kenya. “Everyone in Kenya, especially in the city goes and buys bottled water because they can’t trust coming from the taps,” she said, adding that this can have fatal consequences for human health.

“Not everyone in Kenya, for example, can afford to buy water. Those in the rural areas would still go to the rivers and collect water even though it is not safe. People say we would rather have the water that is unsafe rather than no water at all, they say ‘let me worry about dying later, but let me first take that [unsafe] water because I cannot do without water,’” she said.

Even though water is a basic human right, safe drinking water is increasingly becoming a scarce resource. “Some people fail their societies, they fail their population, water is not well managed and access to water and safe drinking water is a big problem… as an analytical chemist it is very important for me to make sure I’m developing techniques so that we can be able to monitor the quality of water,” she said.

Professor Jane Ngila received a B.Ed degree in science in 1986 and an MSc in chemistry in 1992 from Kenyatta University in Kenya. She obtained a PhD in chemistry in 1995 from the University of New South Wales, Australia. She is a member of the South African Chemical Institute and the Kenya Chemical Society, and previously belonged to the American Chemical Society, the Royal Society of Chemistry, and the Royal Australian Chemical Institute. She is also a member of the advisory boards for Water South Africa, African Utility Week (Clean Power and Water), the International Conference on Pure and Applied Chemistry, and is the UJ representative in the WaterNet/WARFSA/GWP-SA Committee.